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Reprinted  from  The  Journal  of  Comparative  Psycholoqt 
Vol.  II,  No.  2,  April,  1922 


FATIGUE  EFFECTS  AS  MEASURED  BY  SUGAR 
CONTENT  OF  BLOOD^ 

BUFORD  J.  JOHNSON 

From  the  Bureau  of  Educational  Experiments,  New  York  City 

The  purpose  of  this  investigation  was  the  study  of  changes  in 
the  sugar  content  of  the  blood  of  children  as  related  to  different 
kinds  and  amounts  of  activity.  Observations  of  children  in  the 
performance  of  varied  activities  indicate  the  need  of  other  criteria 
of  fatigue  than  diminished  capacity  or  decrease  in  output  in  a 
given  activity  within  a  given  period  of  time.  In  some  cases  the 
stimulating  factors  in  the  situation  lead  to  a  continued  output  that 
is  relatively  good,  though  the  effort  expended  would  indicate  the 
presence  of  fatigue.  In  other  cases  the  decrease  in  output  is 
greater  but  the  assumption  that  there  is  greater  fatigue  present 
does  not  seem  justified.  The  intensity  of  the  stimulus  to  ac- 
tivity is  doubtless  conditioning  the  output  and  interfering  with 
such  a  form  of  fatigue  test.  The  tendency  to  combat  the  onset 
of  fatigue  by  exaggerated  activity  is  often  noted.  This  leads  to 
speeding  up  or  spurts  and  also  to  a  slowing  up  and  increased 
tension  or  force  in  movements.  With  repetition  of  the  activities 
at  short  intervals  the  behavior  of  individuals  tends  to  fall  into 
types  which  emphasize  the  preceding  assumptions. 

There  is  lack  of  uniformity  among  investigators  concerning  the 
change  in  sugar  content  of  the  blood  under  continuous  working 
conditions.  That  a  slight  but  steady  increase  may  occur  in  the 
rate  at  which  adrenalin  enters  the  circulation  during  exercise  is 
held  by  some  writers.  Schneider  and  Havens  (1)  report  an 
increase  in  the  output  of  adrenalin  with  the  onset  of  muscular 
activity.  Cannon  (2)  holds  that  adrenalin  is  secreted  under  the 
stimulatory  effects  of  anticipation,  enters  the  blood  stream,  and 

^  A  briefer  report  of  this  investigation  was  made  at  the  meeting  of  the  American 
Psychological  Association  in  Princeton,  December,  1921. 

y       155 


156 


BUFORD   J.   JOHNSON 


increases  the  functional  capacity  of  muscles.  He  reports  glyco- 
suria after  muscular  exercise  and  also  after  scholarship  examina- 
tions as  evidence  of  increased  sugar  content  of  blood.  Stewart 
and  Rogoff  (3)  found  that  external  manifestations  of  emotional 
excitement  and  presumably,  therefore,  the  visceral  concomitants 
of  emotion  could  be  evoked  in  a  perfectly  normal  manner  in 
animals  whose  suprarenal  glands  have  been  isolated  from  the 
central  nervous  system.  Bainbridge  (4)  reviews  the  experimental 
evidence  and  concludes  that  the  share  taken  by  adrenalin  in 
bringing  about  the  circulatory  and  other  changes  taking  place 
during  exercise,  even  when  this  is  carried  out  under  emotional 
stress,  is  comparatively  small.  In  a  study  of  the  blood  of  dogs 
during  exercise,  Scott  and  Hastings  (5)  found  that  the  concen- 
tration of  sugar  falls  steadily  throughout  the  work  period.  Bro- 
samlen  and  Sterkel  (6)  assert  that  the  contradictory  statements 
concerning  the  change  in  sugar  content  of  the  blood  that  occurs 
after  muscular  exercise  are  due  to  variations  in  interval  between 
end  of  work  and  determination  of  blood  sugar  value.  They  made 
determinations  before  and  after  exercise,  then  followed  this  latter 
determination  by  four  others  made  at  intervals  varying  from  forty 
minutes  to  one  hour  and  twenty  minutes.  The  following  data 
for  healthy  adults  from  their  study  show  the  irregularity  as  to 
decrease  or  increase  in  sugar  content  immediately  after  exercise. 


IMDITIDU  AL 

AGE 

TIME  OF 

FIRST 
DETERMI- 
NATION 

FIRST 

SUGAR 

CONTENT 

TIME 
WORK 
ENDED 

TIME  OP 
SECOND 
DETERMI- 
NATION 

SECOND 

SUGAR 

CONTENT 

VARIATION 

0.  m. 

a.  m. 

0.  m. 

A. 

24 

7:00 

0.086 

7:40 

7:50 

0.082 

-4 

B. 

26 

7:20 

0.093 

8:05 

8:20 

0.085 

-8 

C. 

33 

7:05 

0.088 

7:50 

8:20 

0.102 

+14 

D. 

27 

7:10 

0.078 

7:50 

8:20 

0.074 

-4 

E. 

32 

6:20 

0.096 

6:50 

7:00 

0.104 

+8 

F. 

22 

6:20 

0.094 

7:00 

7:10 

0.082 

-12 

G. 

18 

7:20 

0.076 

8:05 

8:20 

0.087 

+11 

H. 

40 

7:10 

0.082 

8:05 

8:20 

0.082 

0 

I. 

28 

7:10 

0.092 

7:55 

8:05 

0.087 

-5 

J. 

21 

7:00 

0.082 

7:50 

8:05 

0.084 

+2 

FATIGUE   EFFECTS   AND   SUGAR   CONTENT   OF   BLOOD  157 

They  conclude  that  normally  the  blood  sugar  varies  Uttle  when  the 
body  is  at  rest  and  fasting,  but  that  fatiguing  work  by  healthy 
adults  generally  causes  a  sUght  decrease  in  the  sugar  content  of 
the  blood.  The  values  fluctuate  and  the  lowest  value  is  found  at 
varying  intervals  after  the  end  of  the  work.  The  difference 
between  the  rest  value  and  this  lowest  value  amounts  on  the 
average  to  0.020.  There  is  then  a  gradual  increase  in  blood 
sugar,  the  maximum  increase  occurring  from  one  and  one  half 
to  four  hours  after  the  end  of  the  work. 

We  realize  that  our  data  are  not  conclusive  either  as  to  the 
expected  change  in  sugar  content  of  blood  for  children  after  cer- 
tain kinds  of  activities  or  as  to  the  use  of  blood  sugar  determina- 
tions as  a  criterion  of  fatigue.  The  value  of  such  a  method  can 
only  be  determined  by  more  intensive  studies.  So  few  data  are 
available  of  repeated  tests  on  children  under  specified  conditions 
that  we  beUeve  our  records  are  important  as  a  basis  for  further 
investigations. 

PROCEDURE 

In  December,  1920,  eleven  subjects  were  selected  as  being  sus- 
ceptible to  fatigue  effects  to  a  greater  extent  than  other  children 
under  observation.  The  selection  was  made  jointly  with  Dr. 
Edith  Lincoln,  whose  physical  examinations  of  these  children 
indicated  relatively  low  resistance  to  fatigue.  Our  selection  was 
based  upon  decrease  in  output  as  measured  by  psycho-physical 
tests  in  the  laboratory  and  also  upon  apparent  effort  expended 
to  make  the  scores.  Only  eight  subjects,  four  boys  and  four 
girls,  were  available  for  the  complete  experiment  with  the  deter- 
minations of  sugar  content  in  the  blood. 

Two  series  of  laboratory  tests  were  devised,  one  of  relatively 
simple  muscular  tests,  the  other  invohdng  more  complex  mental 
reactions.  An  attempt  was  made  to  establish  a  standard  or  refer- 
ence measure  of  blood  sugar  content  for  each  individual  for  the 
time  of  day  at  which  the  tests  were  to  be  given.  Two  blood  sugar 
determinations  were  made  with  a  three  weeks  interval.  These 
determinations  were  made  by  Dr.  Liggett  Lincoln.  In  making  a 
determination  the  procedure  was  to  bring  the  child  up  to  the 
laboratory  for  obtaining  a  specimen  of  blood,  after  which  he  went 


158  BUFORD   J.   JOHNSON 

back  to  the  school  room  without  any  work  in  the  psychological 
laboratory  on  those  days.  This  was  also  held  to  be  desirable  for 
adapting  the  child  to  such  conditions  so  that  we  might  prevent 
undue  emotional  excitation  on  the  days  of  the  test  series.  These 
children  are  familiar  with  the  laboratory  and  with  the  examiners; 
both  physician  and  psychologist  have  made  studies  of  these 
children  throughout  a  period  of  two  to  three  years  in  each  case. 
Although  two  children  hesitated  about  the  blood  test,  such  ex- 
periences as  the  punctures  for  blood  specimens  have  not  lessened 
the  interest  of  the  children  in  coming  to  the  laboratory,  oppor- 
tunities for  which  they  solicit.  This  desire  was  the  strongest 
incentive  during  the  experiment  for  one  boy  who  has  evinced  fear 
of  even  slight  physical  pain.  Three  weeks  elapsed  between  the 
time  of  the  second  preliminary  blood  test  and  the  first  experi- 
mental series.  The  experiments  were  made  at  the  same  time  of 
day,  between  9:30  and  12  in  the  morning,  keeping  the  order  of 
individuals  the  same  as  far  as  was  possible.  Breakfast  was  not 
omitted.  Diet  lists  showing  the  food  eaten  at  breakfast  had  been 
obtained.  The  physician  considered  the  breakfasts  for  all  the 
children  fairly  standardized  as  to  amount  and  type  of  food.  More 
than  two  hours  elapsed  between  breakfast  and  test  in  each  case. 

A  preliminary  study  was  made  of  the  test  used  in  order  to 
determine  a  series  of  simple  muscular  tests  in  which  practice 
effects  could  be  practically  eliminated,  and  to  acquaint  the  child 
with  the  procedure  so  that  he  would  be  at  a  high  level  of  activity 
between  blood  tests.  In  the  spring  preceding  this  study,  the 
target,  coordination,  tapping,  and  dynamometer  tests  were  given 
to  a  group  of  children  including  those  to  be  used  in  the  fatigue 
experiments.  Trials  were  given  daily  for  nine  school  days, 
Saturday  and  Sunday  intervening  between  the  fifth  and  sixth 
trials.  The  curves  in  figures  1  and  2  show  an  approximate  ehm- 
ination  of  practice  effects  in  tapping  and  coordination.  The 
target  records  for  30  throws  a  day  continued  to  show  marked 
fluctuations  with  little  trend  toward  increased  skill  in  many 
cases.  It  was  a  favorite  performance;  and  the  throwing  of 
100  darts  in  the  fatigue  experiment  offered  an  activity  adequate 
to  the  production  of  muscular  fatigue  activity  which  mere  scores 
do  not  measure. 


TRIALS  * 

FiQ .  1 .  Showing  the  Practice  Effects  in  the  Tapping  Test,  Alternate  Plate 

The  light  lines  are  individual  curves;  the  heavy  line  is  a  group  curve  repre- 
senting the  daily  average  scores. 


Fig.  2.  Showing  the  Practice  Effects  in  the  Coordination  Test 

The  light  lines  represent  individual  scores;  the  heavy  line,  average  scores  for 
the  group. 

159 


n 


160  BUFORD  J.  JOHNSON 

Series  I.  Simple  muscular  tests 


This  series  included:  Target,  100  throws  with  right  hand; 
dynamometer,  10  trials,  left  hand;  tapping,  alternate  plate,  for 
two  minutes  with  right  hand;  tapping,  single  plate,  for  two 
minutes  with  left  hand.  They  were  given  in  the  order  Usted. 
The  target  test  was  that  described  by  the  writer  (7)  in  a  former 
article.  The  dynamometer  and  single  tapping  tests  were  given 
according  to  directions  of  Woolley  and  Fischer  (8).  The  alter- 
nate tapping  plate  (9)  was  so  wired  that  Stoelting  make  and 
break  counters  recorded  separately  the  number  of  taps  for  each 
plate.  The  child  was  instructed  to  strike  first  one  plate  and 
then  the  other.  A  few  taps  were  not  recorded  because  the 
dividing  block  was  struck  instead  of  the  plate  and  also  failure 
to  touch  the  plate  was  noted  even  when  movement  was  made 
approximating  contact. 

Immediately  before  the  child  came  into  the  room  for  the  test- 
ing a  specimen  of  blood  was  obtained  by  the  physician  in  an 
adjoining  room.  The  testing  required  from  twenty  to  twenty- 
five  minutes,  varying  shghtly  for  individuals  because  of  time 
variations  possible  in  two  tests,  the  dynamometer  and  target. 
Another  specimen  of  blood  was  obtained  immediately  after  the 
testing. 

In  table  1  the  sugar  content  for  the  preliminary  blood  tests  is 
shown.  We  have  not  been  able  to  get  definite  standards  as  to 
normal  sugar  content  of  blood  for  the  ages  considered.^  Some 
of  these  children  vary  between  the  first  and  second  tests  as  much 
as  11  mgm.  per  100  cc.  while  others  show  as  little  variation  as 
1  mgm.  per  100  cc.  The  average  sugar  content  for  the  group  for 
the  first  blood  test  was  113.57;  for  the  second  test,  117;  for  the 
third   test,    120.125.    Of   the   six  individuals   considered,   two 

2  Norms  vary  for  different  observers.  Summaries  of  these  normal  values  are 
given  by  A.  Mertz,  Archiv.  fur  Kinderheilkunde,  1920,  Ixviii,  260.  From  2  to  5 
years,  blood  sugar  values  range  from  0.084  to  0.100;  from  2  to  8  years,  0.080  to 
0 .120;  from2  to  14  years,  0 .072  to 0 .113;  from 6  to  14  years,  0 .072  toO  .108.  Mertz, 
A.  and  Romiger,  E.,  Archiv.  fur  Kinderheilkunde,  1921,  Ixix,  105,  give  additional 
data  for  ages  from  7  days  to  1  year,  7  days,  for  which  the  blood  sugar  values  range 
from  0 .068  to  0 .101  with  average  of  0 .081 . 


FATIGUE   EFFECTS  AND   SUGAR   CONTENT   OF  BLOOD 


161 


cases  show  a  decrease  with  variations  relatively  large.  The 
range  of  individual  variations  is  from  0  to  26.  Only  one  case 
shows  a  decrease  in  sugar  content  from  the  preceding  blood  test, 


TABLE  1 
Preliminary  blood  sugar  tests 


G.  P.,  girl. 
J.  S.,  boy.. 

D.  P.,  girl. 
T.  F.,  boy. 
E.G.,  boy. 

E.  R.,  girl. 
J.  M.,  boy. 
M.  D.,  girl. 


Average. 


AOB 

AT  FIRST 

BLOOD 

TEST 


years 

6.04 
7.22 
7.70 
8.29 
8.86 
8.87 
9.14 
11.01 


HEIGHT- 
WEIGHT 
INDEX 


0.95 
0.92 
1.03 
1.18 
1.08 
1.07 
1.18 
1.23 


BLOOD  SUGAR 
(UGM.  PER  100  OC.) 


December      January 
18,  1920  8,  1921 


0.090 
0.139 
0.105 

0.128 
0.112 
0.110 
0.111 


113 .57 


0.100 
0.128 

0.120 
0.120 
0.116 
0.115 
0.120 


117 


TABLE  2 
Series  I.  Simple  muscular  exercise 


TARGET 
BCOBE 

DTNAMO- 

METER 

AVERAGE 

8CORK 

TAPPING  (2  MINtTTE  PERIOD) 

BLOOD  BUGAR 
(mom.  PER  100  OC.) 

Single  plate 

Alternate 
plate 

Before 
exercise 

After 
exercise 

G.  P. 
J.  S. 
D.  P. 
T.F. 
E.G. 
E.R. 
J.M. 
M.D. 

65 

246 
82 
222 
117 
140 
342 
169 

9.3 
8.2 
11.0 
14.1 
11.6 
7.7 
12.6 
12.3 

526 
429 
517 
286 
591 
429 
510 
411 

344 
268 
424 
258 
446 
361 
423 
510 

0.120 
0.130 
0.102 
0.126 
0.120 
0.090 
0.128 
0.145 

0.126 
0.125 
0.110 
0.152 
0.124 
0.120 
0.130 
0.142 

Average 

120.125 

128 .63 

but  this  is  the  largest  variation  found.  Another  case  shows 
an  increase  of  25.  These  two  individuals  seem  especially  sus- 
ceptible to  fatigue  and  are  also  easily  stimulated  to  emotional 
responses.    These  percentages  of  blood  sugar  are  high  as  com- 


162 


BUFORD  J.   JOHNSON 


pared  with  values  usually  given  for  children  and  adults.  They 
exceed  any  blood  sugar  given  by  Brosamlen  and  Sterkel  (10)  for 
healthy  adults.  When  we  average  the  three  blood  sugars  preced- 
ing series  I  for  each  individual  and  get  the  group  average  we 
have  117.89  with  standard  deviation  of  8.44.  The  group  average 
after  the  tests  was  128.63  with  a  standard  deviation  of  12.142. 
The  difference  between  this  and  the  average  of  the  blood  sugar 
determinations  preceding  the  testing  is  8.5  which  equals  1.78 
times  the  probable  error.  Correlation  of  the  blood  sugar  ratings 
immediately  before  series  I  with  those  immediately  after  gives 
r  =  0.53.  There  is  e^ddent  a  sUght  increase  in  blood  sugars  after 
the  simple  muscular  exercise. 

TABLE  3 

Repetition  of  muscular  tests,  April  19,  1921 


DTNAMOMETEE 
AVERAGES 

TAPPING — SEPARATE  PLATES 

BLOOD  8CQAR 
(MGM.  PER 

FOB  RIGHT  HAND 

ADDING 
MA- 

100 CC.) 

Right  hand 

Left  hand 

:2| 

T3.2 

1" 

CHINE 

(3 

S 

(1) 

(2) 

(3) 

(1) 

(2) 

(3) 

< 

T.  F. 

22.2 

19.2 

20.7 

472 

450 

522 

445 

521 

441 

115 

120 

E.  R. 

13.2 

13.4 

12.8 

56 

* 

477 

378 

* 

354 

275 

112 

125 

M.D. 

19.4 

22.0 

18.0 

66 

494 

435 

436 

436 

422 

369 

116 

118 

*  Wire  was  loose  and  record  lost  for  first  trials. 

Two  of  these  children  showed  such  a  large  amount  of  sugar  and 
one  showed  so  great  an  increase  in  sugar  content  that  a  repeti- 
tion of  muscular  tests  was  made.  Blood  sugar  specimens  were 
again  obtained  immediately  preceding  and  following  the  tests. 
The  tests  given  were  tapping,  dynamometer  and  exercise  upon  an 
adding  machine.  The  tapping  was  done  with  both  hands  on 
separate  plates  with  the  board  so  wired  that  records  were  sepa- 
rately kept  for  each  hand.  Three  trials  were  given  with  thirty 
second  intervals.  With  the  dynamometer  fifteen  trials  were  made 
with  the  right  hand.  The  adding  machine  was  arranged  so 
that  1  was  printed  each  time  the  handle  was  pushed  back.  The 
child  was  instructed  to  do  this  as  rapidly  as  possible.     It  was 


FATIGUE   EFFECTS   AND   SUGAR   CONTENT  OF  BLOOD  163 

continued  for  one  minute.    The  sum  printed  was  recorded  as  the 
score. 

The  sugar  content  for  two  of  these  cases  was  not  nearly  so  high 
before  these  activities  as  in  the  first  series  and  there  is  but  a 
slight  change  after  exercise.  The  third  case  has  a  sugar  content 
higher  by  22  than  that  preceding  the  first  muscular  tests  but  does 
not  show  so  great  an  increase  after  exercise,  though  the  blood 
sugar  then  is  the  highest  for  this  child  during  the  experiment. 
A  slight  increase  in  blood  sugar  after  exercise  is  found  for  all 
three  subjects. 

Series  II 

The  second  series  for  producing  fatigue  from  more  complex 
reactions  involving  little  muscular  exercise  was  given  May  17, 
1921.  The  same  procedure  was  followed  in  obtaining  blood 
specimens  both  before  and  after  the  activities  in  the  laboratory. 
The  tests  were  given  in  the  following  order:  coordination, 
discrimination,  memory  for  digits,  and  substitution.  In  the 
coordination  test  (fig.  3)  the  child  was  instructed  to  trace  a  path 
without  touching  the  sides,  but  in  tracing  a  given  segment  to 
make  a  stroke  of  the  pencil  to  the  beat  of  the  metronome.  This 
was  set  at  one  hundred  beats  per  minute.  An  actual  record 
made  during  the  experiment  is  shown  in  figure  3.  Number 
of  contacts  and  time  were  recorded. 

The  discrimination  test  involved  the  sorting  of  fifty-two  ordi- 
nary playing  cards.  In  the  center  of  each  card  was  cut  a  dia- 
mond-shaped hole.  The  holes  were  so  cut  that  in  thirteen  cards 
the  long  axis  of  the  diamond  was  lengthwise  the  card;  in  thirteen 
cards  it  was  crosswise  the  card;  in  thirteen  cards  it  extended  in 
the  diagonal  from  the  upper  right  to  the  lower  left;  in  the  re- 
maining cards  from  the  upper  left  to  the  lower  right.  A  wooden 
receptacle  of  five  open  stalls  was  clamped  to  a  table  under  an 
adjustable  screen  so  that  the  stalls  and  cards  could  not  be  seen. 
The  cards,  carefully  shuffled,  were  placed  in  the  end  stall  at  the 
left.  The  subject  was  instructed  to  take  from  the  top  of  the  pack 
one  card  at  a  time  with  the  left  hand  and  while  holding  it  in  this 
hand  to  run  the  thumb  and  forefinger  of  the  other  hand  around 


164  BUFOKD   J.   JOHNSON 


Fig.  3.  An  Actual  Record  in  the  Coordination  Test 


FATIGUE   EFFECTS   AND   SUGAR   CONTENT  OF  BLOOD  165 

the  edge  of  the  hole.  He  was  then  to  place  the  card  in  that  stall 
designated  for  cards  with  the  diamond  in  that  position.  The 
sorting  continued  in  this  manner  until  all  the  cards  had  been 
distributed.  The  record  sheet  in  figure  4  shows  the  type  of  errors 
made. 


G.P  . 

7-  17" 

J.  S. 

11*20" 

O.P.      7  7 

tiO  0O 

\:^9  4  5  11 

\:\i  0    0  2 

W()  Po 

0*  '- 

00      1 

5       1 

1     0 

0'  ^ 

00       1 

8      5 
1     2 

06122 

{:J  1  0  9  0 

O  0      0 

1      1 

OO    0 

0      1 

03      4      1      1 

SCORE 

22 

27 

29 

t.F. 

8*  35' 

E.  C. 

14*32" 

J.  M.     6*10** 

^1      0 

'       0 

0O 

0       1 

tiO   0O 

\^]0     2       1       0 

09     U 
00       1 

3      0 
9      0 

0'    12 

0y     0 

4      0 
1      ) 

Oo      i      2      3 
(^3      2     10      1 

o°   ° 

0     13 

OO    0 

0     U 

O  0      0      0      i 

SCORE 

38 

M.D. 

39 

6*55- 

38 

C^lJ     0      1      0 

Ot    13 

00      0 

4      0 
8      0 

o°    <» 

0     13 

SCORE 

46 

FiQ.  4.  Record  of  Time  and  Placements  in  the  Discrimination  Test 

In  the  test  of  memory  for  digits  the  procedure  followed  was 
that  described  in  the  monograph  by  Woolley  and  Fischer"  (11) 
previously  mentioned.  The  substitution  blank  used  was  a  sym- 
bol form  devised  by  Dunlap.    A  record  made  by  the  youngest 


166 


BUFORD   J.   JOHNSON 


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Fig.  5.  Record  Made  by  the  Youngest  Child  in  the  Substitution  Test 


FATIGUE   EFFECTS   AND   SUGAR   CONTENT   OF   BLOOD 


167 


child  is  shown  in  figure  5.     It  was  required  that  sjinbols  be 
substituted  for  symbols. 

TABLE  4 
Series  II,  May  17,   1921 


MOTOR  COORDINATION 
TEST 

FORM  DISCRIMINATION 

MEMORY  FOR 

DIGITS 

SUBSTITCTION 
(FORM  1) 

Time 

Number  of 
contacts 

Time 

Score 

Span 

Score 

Time 

Errors 

G.P. 

1'26" 

38 

7' 17" 

20 

5 

40 

4' 16" 

0 

J.  S. 

I'll" 

36 

11' 20" 

27 

6 

66 

4' 10" 

0 

D.  P. 

I'SO" 

20 

7'   7" 

29 

7 

100 

3'    4" 

1 

T.F. 

1'29" 

42 

8' 35" 

38 

4 

31 

2' 43" 

0 

E.G. 

I'lO" 

38 

14' 32" 

39 

9 

175 

3' IS" 

0 

J.M. 

1'20" 

14 

6' 10" 

38 

9 

164 

3'    4" 

2 

M.D. 

1'    4" 

26 

6' 55" 

46 

7 

101 

2' 28" 

0 

TABLE  5 
Series  II.  Blood  sugar,  blood  pressure  and  urinalysis,  May  17,  1921 


BLOOD  SUGAR 

(mgm. per 
100  cc.) 

PRES8DBE 

URINALYSIS 
AFTER 

PREVIOUS  BLOOD  PRESSURES 

EXERCISE 
FOB  SUGAR 

Before 
exercise 

After 
exercise 

Before 
exercise 

After 
exercise 

1918-19 

1919-20 

1920-21 

G.P. 

85 

89 

88 
60 

102 
62 

None 

78 
58 

78 
56 

92 
62 

90 
70 

J.S. 

90 

88 

108 

74 

90 

68 

None 

90 

58 

94 

72 

D.  P. 

81 

84 

96 

72 

96 
68 

None 

90 
58 

92 
60 

88    90 
62    56 

92 
68 

T.F. 

88 

90 

102 

72 

98 
76 

None 

106 
66 

110 
66 

96 

58 

104 
76 

E.G. 

92 

85 

110 
76 

110 

72 

None 

98 
76 

J.M. 

100 

102 

96 
64 

100 
66 

None 

78 
66 

82 
66 

90    90 
64    64 

98 
76 

M.D. 

101 

110 

122 

78 

98 

78 

None 

88 
64 

86 
64 

88 
62 

106 

78 

168  BUFORD  J.  JOHNSON 

In  table  5  it  is  shown  that  the  sugar  content  immediately 
preceding  these  tests  was  lower  in  each  case  than  in  previous 
determinations.  The  variation  after  exercise  is  less  than  that 
between  any  other  two  measures  except  in  two  cases. 

We  have  no  explanation  for  the  fall  in  sugar  content  unless  it 
is  due  to  seasonal  variation,'  such  as  reported  by  Strouse  (12). 
The  blood  pressure  and  urinalysis  add  httle  to  the  interpretations. 
It  might  be  argued  that  emotional  excitation  in  preceding  de- 
terminations influenced  the  sugar  content.  That  a  child  should 
be  so  much  affected  in  four  or  six  blood  tests  and  not  in  the  next 
can  not  be  assumed.  This  fall  is  noted  for  the  children  who  had 
supplementary  tests  and  for  those  who  did  not.  The  preceding 
activities  and  breakfasts  were  approximately  the  same  as  in 
preceding  tests. 

DISCUSSION   AND   SUMMARY 

The  range  in  chronological  age  is  such  as  to  invaUdate  direct 
comparisons  of  output  and  changes  in  sugar  content.  We  give 
the  records  to  indicate  the  actual  work  done  by  each  individual. 
In  the  preliminary  study  of  tests  for  use  in  this  investigation  we 
found  a  decrease  in  tapping  scores  for  the  fourth  period  of  thirty 
seconds  as  compared  with  the  first  period.  The  graphs  in  figure 
6  show  this  diminished  output  for  each  of  the  nine  practice  peri- 
ods. While  the  decrease  fluctuates  from  day  to  day,  there  is 
no  tendency  towards  a  lessening  of  this  difference  with  increas- 
ing practice.  Individuals  vary  as  to  the  period  in  which  least  ca- 
pacity is  shown.  If  a  higher  level  of  efficiency  is  maintained  for 
the  first  two  periods  there  often  results  a  marked  decrease  in  the 
third  period,  with  perhaps  a  slight  increase  for  the  fourth  or 
final  period.  Others  show  a  gradual  diminution  in  capacity 
from  the  first  to  the  final  period.  The  fluctuations  in  the  group 
curves  II,  III,  and  IV  are  probably  due  to  these  individual 
differences. 

'  Strouse  found  that  the  average  blood  sugar  readings  were  higher  in  the  cooler 
part  of  the  year.  Daily  variations  of  blood  sugar  percentage  occurred  in  five 
normal  persons.    These  variations  seem  to  depend  on  changes  in  the  weather. 


FATIGUE   EFFECTS   AND   SUGAR   CONTENT   OF   BLOOD 


169 


Fig  .  6 .  Showing  the  Daily  Scores  for  Thirty-Second  Periods  in  the  Tapping 
Test,  Alternate  Plate,  for  Nine  Children 

I,  Average  daily  score  for  first  period;  II,  for  second  period;  III,  for  third 
period;  IV,  for  fourth  period. 

TABLE  6 
Individual  variations 


FIRST  AND 

SECOND 

PBELIMI- 

NABT 

SECOND 
PRELIMI- 
NARY AND 
BEFORE 
SERIES  I 

BEFOHB 

AND  AFTER 

SERIES  I 

AFTER 
SERIES  I 

AND 
BEFORE 
SERIES  II 

BEFORE 
AND  AFTER 
8BBIES  II 

AVERAGE 
DEVIATION 

G.  P 

10 
-11 

-8 
4 
5 
9 

10 

2 

6 

0 

-26 

13 

25 

6 
-5 

8 
26 

4 
30 

2 
-3 

-41 
-35 
-29 
-64 
-32 

-30 
-41 

4 

-2 
3 
2 

-7 

2 
9 

14    2 

J.S 

11  0 

D.  P 

13  3 

T.F 

24  5 

E.C 

10  2 

E.R 

J.  M 

10.4 

M.D 

17  4 

Average 

7.83 

11.71 

10.5 

38.85 

4.14 

14.43 

170 


BUFORD  J.   JOHNSON 


The  individual  variations  shown  in  table  6  indicate  little 
stability  in  blood  sugar  for  a  given  individual  under  the  condi- 
tions of  the  experiment.  We  find  that  a  child  may  show  a  rela- 
tively high  sugar  content  before  exercise  and  either  slight  or 
marked  increase  after  exercise.  Relatively  low  content  of  sugar  is 
also  found  preceding  exercise  with  a  rise  of  as  much  as  0.030  after 
exercise.  In  some  cases  a  slight  decrease  is  found.  We  do  not 
know  whether  such  variations  are  due  to  a  slow  rise  or  to  a  slow 
fall  in  sugar  content;  to  the  amount  and  kind  of  activity;  or  to 
affective  factors.  Individual  E.  C,  who  has  been  characterized 
as  fearful  of  slight  physical  pain  and  with  whom  the  physician 
reasoned  for  some  minutes  before  securing  assent  to  the  blood 
test  preceding  series  I,  shows  the  least  average  variation.  The 
change  in  sugar  content  as  shown  by  determinations  made  on  the 
same  day  preceding  and  after  exercise  is  less  on  the  average  than 
the  total  group  variation.  This  group  average  is  heavily  weighted 
by  the  variation  in  blood  sugars  obtained  April  19,  1921,  and 
May  17,  1921.  This  we  attribute  to  elevation  of  temperature. 
The  weather  conditions  on  the  days  of  the  experiment  were  as 
follows : 


DECEM- 
BER 18, 
1920 

JANU- 
ARYS, 

1921 

JANU- 
ARY 26, 
1921 

APRIL  19, 

1921 

MAY  17, 

1921 

Temperature  at  9  a.m.  F 

Humidity  at  S  a.m 

29.0 
0.66 
29.71 

39.0 
0.96 
29.72 

12.0 

0.52 
30.45 

39.0 
0.90 
29.92 

48.0 
0.65 

Barometer  at  8  a.m 

30.22 

The  effects  of  this  seasonal  change  in  sugar  content  as  related  to 
the  optimal  schedule  of  activities  for  school  children  merits  in- 
vestigation. If  we  exclude  this  factor,  the  change  in  sugar 
content  for  series  I,  simple  muscular  exercise,  appears  more 
significant.  Two  children  stand  out  from  the  group  with  regard 
to  the  internal  conditions  under  which  work  is  performed. 
In  the  preUminary  practice  series  for  tapping  test,  alternate  plate, 
the  relative  capacity  of  these  two  children  is  shown  by  the  follow- 
ing results. 


FATIGUE   EFFECTS   AND   SUGAR   CONTENT   OF   BLOOD 


171 


Average  total  output 

Average  daily  output 

Average  for  1st  30  outputs. 
Average  for  4th  30  outputs. 


GROtP 

E.  R. 

3769 .33 
418.80 
113.79 
100 .78 

3377.00 

375  .00 

99.44 

92.55 

2552 .00 

364  .00 

98.00 

92.71 


It  is  evident  that  the  stimulating  effects  of  environmental  factors 
are  widely  different  for  different  children. 

Conclusions  as  to  the  influence  of  different  kinds  and  amounts 
of  activities  upon  the  sugar  content  of  the  blood  would  be  un- 
warranted by  our  data.  We  believe  that  they  indicate  a  method 
of  investigation  that  may  clarify  the  concepts  of  fatigue  and  lead 
to  a  reformulation  of  the  factors  involved  in  fatigue  effects. 
It  seems  essential  that  we  make  successive  determinations 
throughout  a  stated  period  of  the  day  and  over  a  period  of  time 
sufficiently  long  for  us  to  know  what  the  normal  changes  are  for 
the  individuals  under  observation.  Determinations  should  be 
made  at  short  intervals  preceding  and  following  specific  activities 
which  vary  in  complexity  and  in  motivation. 

REFERENCES 

(1)  Schneider,  E.  C,  and  Havens,  L.  C.  :  Changes  in  the  blood  after  muscular 

activity  and  during  training.    Amer.  Jour.  Physiol.,  1915,  xxxvi,  256. 

(2)  Cannon,  W.  B.:  Bodily  changes  in  pain,  hunger,  fear  and  rage,  211. 

(3)  Stewart,  G.  N.,  and  Rogoff,  J.  M.:  Further  observationte  of  relation 

of  adrenals  to  certain  experimental  hyperglycemias.    Amer.    Jour. 
Physiol.,  1920,  Ivii,  376. 

(4)  Bainbridge,  F.  a.:  The  physiology  of  muscular  exercise,  128-138. 

(5)  Scott,  E.  L.,  and  Hastings,  A.  B.  :  A  study  of  the  sugar  and  oxygen  relation- 

ships in  the  blood  of  dogs  during  exercise.    Proc.  Soc.  Exper.  Biol, 
and  Med.,  1920,  xvii,  120-122. 

(6)  Brosamlen,  O.,  and  Sterkel,  H.:  Der  Einfluss  von  Muskelarbeit  auf  den 

Blutzuckergehalt.    Deutsches  Arch,  fur  Klin.  Med.,  1919,  cxxx,  360- 
363,  371-372. 

(7)  Johnson,  B.:    Practice  effects  in  a  target  test — a  comparative  study  of 

groups  varying  in  intelligence.    Psychol.  Rev.,  1919,  xxvi,  300-316. 

(8)  WooLLEY,  H.  T.,  and  Fischer,  C.  R.:  Mental  and  physical  measurements 

of  working  children,  52,  75. 

(9)  DuNLAP,  K.:  Improved  form  of  steadiness  tester  and  tapping  plate.    Jour. 

of  Exper.  Psychol.  1921,  vol.  IV,  430-432. 
(10)  Brosamlen,  O.,  and  Sterkel,  H.:  0-p.  cit.,  p.  360-363. 
'XI)  WoOLLEY,  H.  T.,  AND  FiSCHER,  C.  R.:  Op.  cit.,  p.  123. 
U -)  Strotjse,  S.:  Some  variations  in  normal  blood  sugar.    Archiv.  Int.  Med., 

1920,  xxvi,  758. 


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